Even as a growing fleet of U.S. warships contends with flare-ups in the Middle East, a vital rebalancing of America’s military and strategic interests toward the Asia-Pacific is proceeding apace, the four-star combatant commander overseeing the Pacific said Wednesday during a visit to San Diego.

North Korea’s nuclear weapons program, a developing strategic partnership between the U.S. and India, and plans to base a fleet of Littoral Combat Ships in Singapore are among a host of factors boosting the region’s profile, but the rising economic and military power of China is paramount, said Adm. Samuel Locklear, head of U.S. Pacific Command.

His command, headquartered in Hawaii, has operational control over some 350,000 service members from all branches of the armed forces, at installations from San Diego to Okinawa, Japan, and beyond.

China has long been walled off from the world, Locklear told the San Diego Military Advisory Council. As it grows into a global economic power, “how they come out behind these walls will be a critical aspect of our foreign and our military policy in the Pacific.”

During that transition, “how does a mature power, the United States, a global power, how do we accept them? If you look back at history on how a mature power accepted a rising power without conflict, there are not many examples of it,” Locklear said.

Even as it flexes its own might in the region, the U.S. has been making overtures to the Chinese military. On Wednesday, Defense Secretary Leon Panetta met with Chinese military cadets and the man presumed to be the next Chinese leader, Xi Jinping. China was also invited to the next Rim of the Pacific international military exercise, the largest in the world.

“The stakes are pretty high on this one,” Locklear said. “Our military presence in that region is more critical than it has been since the end of World War II, to be able to properly shape or at least influence the rise of China in a way that makes sense.”

To that end, a rebalancing of U.S. defense assets toward the Pacific is under way, and San Diego is its doorstep, Locklear said. “The forces that are trained and equipped and nurtured here by this magnificent community are very critical to the execution of our strategies in that region,” Locklear said.

The Navy aims to homeport about 60 percent of its forces on the West Coast, up from about 50 percent. “We are already on the high side of the half and half like we used to have,” Locklear said. “But it won’t be done in a vacuum. It has to be done in recognition that we have other things in the world that we will still continue to do.”

Among other changes, about 250 Marines began this year to rotate on six-month tours to Darwin, Australia. Eventually as many as 2,500 at a time could deploy there. The Army corps based at Fort Lewis, Wash., has been redesignated for the Pacific. And Marines and soldiers formerly deployed to Afghanistan are streaming back to home installations such as Camp Pendleton, freeing them for regional operations that have been on the backburner during a decade of combat.

In the post Iraq and Afghanistan war era, “we’re not really looking for additional bases anywhere in the Asia-Pacific. We are looking for opportunities to partner with our friends and allies in ways that allow a certain level of burden sharing,” Locklear told San Diego reporters. For instance, the Philippines, Indonesia and Vietnam are among countries whose governments have expressed interest in expanding security ties with the United States.

The rebalancing of the worldwide Navy fleet was intended to send more aircraft carriers, destroyers and cruisers to Asia-Pacific over the next four years, according to a briefing this summer by Adm. Jonathan Greenert, the Navy’s top officer. But the region slated to get the most ships overall was the Persian Gulf — going from 25 up to 34.

New tensions in the Middle East coupled with a temporary shortage in deployable aircraft carriers have stalled the shift to the West Coast, said retired Vice Adm. Pete Daly, chief executive of the U.S. Naval Institute.

“Demand for naval forces is up, and the big issue right now is the tension between the demands of the Middle East and the so-called pivot to the Pacific,” said Daly, who formerly commanded a strike group in San Diego.

For example, the aircraft carrier Stennis was forced to deploy again four months earlier than planned after returning in March from a previous tour, leaving for twice as long as anticipated on an eight-month assignment in the Persian Gulf.

“The Navy had planned by this point and the joint staff ... that they would be able to shift assets from the Gulf to the Pacific,” and no longer have two full carrier groups in the Middle East, Daly said. Now “the feeling is we are going to have to have this additional carrier presence for some time.

“People in the Middle East, in Syria and Iran, Yemen and other hot spots, just didn’t get the pivot memo,” Daly said.

Exacerbating the problem is that instead of 11 deployable aircraft carriers, the U.S. is making do with 10 until 2015 when the Gerald R. Ford comes online, he noted. “There’s not enough to go around right now.”

The confluence of strategic responsibilities and finite resources is a balancing act, Locklear said.

“The Pacific didn’t get any smaller. It’s still a long ways to get people there. .. It takes a lot of gas, it takes a lot of air power. It takes a lot of ships.

“So on the one hand we have to balance trying to build the capacity of our allies ... to be able to help our future partners like we hope China would be a future security partner,” he said. “But on the other hand we have to balance our ability to respond to crises, to contingencies, and if necessary to protect America’s interests and to fight and win wars when we are told to do that.